Membrane bioreactors (MBR) attract more and more attention in wastewater treatment and water reclamation industry mainly due to exceptional effluent quality. Membrane technology combines biological degradation of organic compounds which is carried out by suspended growth microorganisms and physical separation of particles which is achieved by porous membranes in a single process. In MBR systems, porous membranes are prone to accumulate biological layered-structure called biofilm, thus results in membrane biofouling. Membrane biofouling causes several adverse effects such as effluent flux reduction, increasing energy consumption for wastewater treatment and air scouring, and raising the cost of chemical cleaning and membrane replacement. Quorum quenching (QQ) is an emerging biological method to control biofilm formation. One of the quorum quenching techniques is applying bacteria that can degrade signalling molecules in order to prevent biofilm from maturation through the inhibition of quorum sensing regulated secretion of extracellular polymeric substances (EPSs).<br/> <br/>In this study, three QQ microorganisms (A9, A12 and B11) were isolated from activated sludge of a municipal treatment plant and one QQ microbe was collected from an environmental water sample. All of these QQ bacteria can remove at least 70% of 8 different acyl homoserine lactone (AHL) molecules (100 nM) within 180 min. Their QQ activities remained when immobilized in poly(vinyl alcohol)/sodium alginate (PVA/SA) beads although AHLs removal rates were declined compared to QQ bacteria suspension. After addition of the QQ beads, successful reduction of transmembrane pressure accumulating rate was also achieved in a continuous operated MBR.

Evaluating acyl homoserine lactones removal efficiencies of isolated quorum quenching bacteria and their application for biofouling control in membrane bioreactors

2019 Fall National Meeting

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